1. Field of the Invention
The present invention relates to the selective and efficient removal of primary and secondary hydroperoxide impurities from tertiary alkyl hydroperoxides which are produced by the oxidation of branched hydrocarbons. In particular, the primary and secondary hydroperoxide impurities are removed by contacting a mixture containing these impurities and tertiary alkyl hydroperoxide with a carboxylic acid derivative, preferably an anhydride such as maleic anhydride in the absence of water, and thereafter reacting the resulting mixture with a base.
2. Description of the Prior Art
There a number of known methods for the removal of primary and secondary hydroperoxide impurities from tertiary hydroperoxides including distillation, thermal treatment, caustic treatment, and the like. These prior procedures, however, have definite disadvantages in that they are not sufficiently selective for the removal of the undesired impurities and require long reaction of residence times. The prior methods tend to destroy large amounts of the desired tertiary alkyl hydroperoxide during the purification process.
An especially pertinent patent in this area is U.S. Pat. No. 4,891,101 which shows a method for the removal of primary and secondary hydroperoxide impurities by contacting a tertiary alkyl hydroperoxide containing the impurities with a carboxylic acid derivative such as the anhydride and a basic compound such as sodium hydroxide. It is taught that approximately 80% of the primary and secondary hydroperoxides can be removed by the method shown in the patent. A disadvantage is that the process described requires large reactor sizes and results in a large consumption of the carboxylic acid derivative due to the fact that the reactions are conducted in the presence of a substantial excess of water. As a result, a significant amount of the acid anhydride reacts with the water to form acid which in turn reacts with alkali present to form salts. In fact, the state of the art is such that there exists room for improvement in the economies and efficiencies of the separation of primary and secondary hydroperoxides from tertiary alkyl hydroperoxides.